Electric switch with a movable body of conductive fluid under pressure



y 1964 J. L. GRUPEN ELECTRIC SWITCH WITH A MOVABLE BODY OF CONDUCTIVE FLUID UNDER PRESSURE Filed July 24, 1961 INVENTOR.

2/4/1455 1 @IGWPEA/ prom/5y United States Patent 3,142,739 ELECTREQ SWITCH WETH A MGVAELE BODY 0F (IGNDUCTEVE FLUTE UNDER PRESSURE James L. Grupen, Giendora, Calif. (1269 Lynn Way, Sunnyvaie, Qalif.) Filed Early 24, 1961, Ser. No. 126,225 9 Uaims. (Cl. 200-152) This invention relates to an electric switch and has for an object to provide a current-closing and -opening device that is non-arching, especially when opening, thereby providing a switch capable of long and efficient use.

Deterioration effects of the break action of electric switches have, in some measure, been overcome in the tilting mercury switch which, although advantageous for many uses, is confined to use under stationary conditions. Moreover, such tilting switches are not dependable where shock may be present.

Recognizing the faults above, the present invention has for another object to provide an electric switch that embodies a fluid conductor; for example, a quantity of mercury or ionized gas, that not only has positive position in both the make and break positions of the switch, but is so confined that the same acts in a manner similar to a solid conductor, yet obviates deterioration and loss of efliciency due to sparking and other such undesired effects.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construc tion and novel combinations and arrangements of parts, which will more fully appear in the course of the following description, and which is based on the accompanying drawing. However, said drawing merely shows, and the following description merely describes, one embodiment of the present invention, which is given by Way of illustration or example only.

In the drawing, like reference characters designate similar parts in the several views.

FIG. 1 is a longitudinal sectional view of an electric switch according to the present invention and shown in the off or open position thereof.

FIG. 2 is a similar View showing the switch on or closed.

The electric switch that is illustrated comprises, generally, a housing 5 constituting one terminal of the switch, a plunger 6 constituting the other terminal, and a body of electrically conducting fluid 7 confined by the housing to form part of the plunger 6 and having makeand-break association with the housing according to the position of the plunger therein.

The housing is preferably formed of brass or other suitable conductive material, the same having a bore 10 that may be closed by an end wall 11 and defined by a cylindrical skirt 12. An extension 13 on wall 11 constitutes a terminal to which a conductor may be connected in the usual way. An air-bleeding orifice 14 in wall 11 obviates air entrapment in bore 10 during operation of the switch. Adjacent the open end of the bore, the skirt 12 is provided with a non-conductive liner 15 that has its inner bore 16 flush with the bore 10. Said liner is preferably press-fitted into place and may be retained in the housing by a retaining flange 17 that is spun over the end thereof. The liner 15 is preferably hard and substantially inelastic, and may be made of acrylic resin, polyarnide resin, acetal resin, tetrafluorethylene polymer plastic, and other such synthetic resins and plastics that may be finished to have a smooth, non-porous inner bore surface.

3,142,739 Patented July 28, 1964 The plunger 6 comprises a stem 18 that has a reduced end 19 on which is aiiixed a piston 20 having an outer annular groove 21 that is fitted with an -O-ring 22 to form a seal between said piston 29 and the bore 10, 16 of the housing 5, with a piston 23 that has an outer annular groove 24 that is fitted with an O-ring 25 to form a seal between piston 23 and the bore 16 of the liner 15, and with means 26 that retains said piston 23 on stem 18 on which it has a sliding fit.

Said pistons 20 and 23 are longitudinally spaced so as to accommodate the body of fluid 7 therebetween, the means 26 including a spring washer 27 or the like for resiliently biasing the piston 23 toward the piston 20 and, thereby, compressing the fluid 7 in the space between the pistons so that, upon endwise movement of the plunger 6, the fluid 7 will move therewith as a conductive component of the plunger. Since the stem 18 is made of metal or other conductive material, the same constitutes the terminal of plunger 6, and it will be clear that the fluid 7 electrically connects the housing 5 and the stem 18 when the plunger is in the retracted position of FIG. 1. Because the mass of fluid 7 moves as a confined body of material, projection of the plunger brings the same into contact only with the dielectric liner 15, opening the circuit across terminals 13 and 18.

The pistons 20 and 23 are made of dielectric material similar to the material of liner 15 and the diametral size thereof is made to be clear of bore 10, 16, dependence being placed on the rubber O-rings 22 and 25, on each side of the fluid body 7, to seal against egress of fluid from said body past the O-rings. To insure a positive seal between the piston 23 and stem 18, an O-ring seal 28 is disposed in a seat 29 formed in piston 23. Said O-ring is shown as retained by a washer plate 30 against which the spring washer 27 presses, but the seat 29 may be formed as an internal annular groove instead of an endopen seat, as shown.

By bevelling the rim 31 of the piston 20 on the side thereof engaged by the conductive fluid body 7, a small amount of fluid can be made to present a wide area of contact with the bore 20.

It will be clear that loss of fluid is either wholly prevented by O-rings 22, 25 and 28, or greatly minimized. The means 26 compensates for any losses that may occur byurging the piston 23 in a direction to retain the pressure bias on the fluid.

While the foregoing has illustrated and described What is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. An electric switch comprising a conductive housing having a bore provided with a dielectric liner, a movable plunger in said bore and provided with a conductive stern spaced from said bore, a body of conductive fluid material wholly disposed Within the confines of the bore and carried by and bodily movable, in its entirety, with the plunger in electrical contact with the stern and in contact with the mentioned bore to electrically connect the housing and stem in one position of the plunger and electrically disconnect said stem from the housing by contacting the liner in another position of the plunger, and means carried by the plunger to impose pressure on said body of material and force the same into intimate electrical contact with both said bore and said stern in all portions of the plunger.

2. An electric switch according to claim 1 in which the conductive fluid material comprises mercury.

3. An electric switch according to claim 1 in which the conductive fluid material comprises ionized gas.

4. An electric switch comprising a conductive housing having a bore, a dielectric liner in said housing and having a bore forming an extension or the housing bore, a conductive stem disposed and movable axially in said housing and clear of said bores, a first dielectric piston aflixed to said stem, a second dielectric piston slidably mounted on the stem, at body of conductive fluid material between said pistons, means carried by the stem to bias the slidably mounted piston in a direction to press said body of fiuid material against the first piston and into firm electrical engagement with the stem and with the housing bore in one position of the stern, and into firm electrical engagement with the same and into contact with the liner bore in another position of the stem.

5. An electric switch according to claim 4 in which the two pistons carry means to seal against said bores and said stem to retain the body of liquid in position to be moved by the pistons upon movement of the stem.

6. In an electric switch having a housing with a bore having a conductive part and a non-conductive part, a switch plunger fitted into said bore and provided with two longitudinally spaced pistons wholly within and in a body of conductive fluid in the space between said pistons electrical contact with the bore, means engaged with one piston to resiliently bias the same toward the other to place i; the fluid therebetween under pressure and a stem mounting said pistons in electrical contact with the fluid.

7. In an electric switch according to claim 6, said pistons being dielectric.

8. In an electric switch according to claim 6, said pistons being dielectric, and sealing rings carried by said pistons and sealing between said pistons and the housing bore.

9. In an electric switch having a housing with an openended cylindrical bore therein, with conductive and nonconductive longitudinally arranged parts, a dielectric piston slidingly fitted in said bore, a conductive stem aiiixed to said piston and extending outwardly of the open end of References Cited in the file of this patent UNITED STATES PATENTS Sissenwine et al Aug. 5, 1952 McLaughlin Oct. 11, 1955 

1. AN ELECTRIC SWITCH COMPRISING A CONDUCTIVE HOUSING HAVING A BORE PROVIDED WITH A DIELECTRIC LINER, A MOVABLE PLUNGER IN SAID BORE AND PROVIDED WITH A CONDUCTIVE STEM SPACED FROM SAID BORE, A BODY OF CONDUCTIVE FLUID MATERIAL WHOLLY DISPOSED WITHIN THE CONFINES OF THE BORE AND CARRIED BY AND BODILY MOVABLE, IN ITS ENTIRETY, WITH THE PLUNGER IN ELECTRICAL CONTACT WITH THE STEM AND IN CONTACT WITH THE MENTIONED BORE TO ELECTRICALLY CONNECT THE HOUSING AND STEM IN ONE POSITION OF THE PLUNGER AND ELECTRICALLY DISCONNECT SAID STEM FROM THE HOUSING BY CONTACTING THE LINER IN ANOTHER POSITION OF THE PLUNGER, AND MEANS CARRIED BY THE PLUNGER TO IMPOSE PRESSURE ON SAID BODY OF MATERIAL AND FORCE THE SAME INTO INTIMATE ELECTRICAL CONTACT WITH BOTH SAID BORE AND SAID STEM IN ALL PORTIONS OF THE PLUNGER. 